1. Field of the Invention
The present invention generally relates to a liquid crystal module. More specifically, the present invention relates to a liquid crystal module having a printed wiring board attached to a rear frame.
2. Background Information
A conventional liquid crystal module is installed into a television set or a personal computer. The liquid crystal module includes a rear frame and a main printed wiring board. The rear frame includes a plurality of support protuberances. The main printed wiring board is supported on the support protuberances and fixed with screws. The printed wiring board is positioned before the printed wiring board is fixed with the screws. The positioning is accomplished by pressing end faces of the printed wiring board against a plurality of lift-up positioning tabs formed separate from the support protuberances.
With a conventional printed wiring board attachment apparatus, a trapezoidal seat is formed by cutting and lifting up a bottom face of a chassis made of sheet metal. A printed wiring board is positioned by fitting a notch formed in the printed wiring board to a guide tab that sticks up from the trapezoidal seat. Then, the printed wiring board is fixed to the trapezoidal seat with a screw (see Japanese Laid-Open Utility Model Publication No. H1-174980, for example).
With another conventional printed wiring board attachment structure, several protrusions with an inverted L shape are provided to sheet metal by cutting and lifting. Edges of a printed wiring board are fixed to the protrusions. A step portion for positioning the printed wiring board is provided to a horizontal part of the protrusion. An end edge of the printed wiring board is mated with the step portion (see Japanese Laid-Open Utility Model Publication No. S57-161289, for example).
When the printed wiring board is positioned by forming the lift-up positioning tabs in the rear frame as with the conventional liquid crystal module, light leaks to the back of the liquid crystal module through openings formed in portions of the rear frame 1 where the lift-up tabs are formed. Also, since the lift-up tabs are prone to deformation, it is difficult to position the printed wiring board accurately.
Even when the printed wiring board attachment technique of Japanese Laid-Open Utility Model Publication No. H1-174980 is applied to a liquid crystal module, light also leaks out through openings formed in the portions where the trapezoidal seat is formed by cutting and lifting. Also, even if the printed wiring board attachment technique of Japanese Laid-Open Utility Model Publication No. S57-161289 is applied, light also leaks out through openings formed in the portions where the inverted L-shaped protrusions are formed by cutting and lifting.
In view of the above, it will be apparent to those skilled in the art from these disclosures that there exists a need for an improved liquid crystal module. This invention addresses this need in the art as well as other needs, which will become apparent to those skilled in the art from these disclosures.